Function newContext

driver_js.go:36–195

(sampleRate int, channelCount int, format mux.Format, bufferSizeInBytes int)

}

func newContext(sampleRate int, channelCount int, format mux.Format, bufferSizeInBytes int) (*context, chan struct{}, error) {
	ready := make(chan struct{})

	class := js.Global().Get("AudioContext")
	if !class.Truthy() {
		class = js.Global().Get("webkitAudioContext")
	}
	if !class.Truthy() {
		return nil, nil, errors.New("oto: AudioContext or webkitAudioContext was not found")
	}
	options := js.Global().Get("Object").New()
	options.Set("sampleRate", sampleRate)

	d := &context{
		audioContext: class.New(options),
		mux:          mux.New(sampleRate, channelCount, format),
	}

	if bufferSizeInBytes == 0 {
		// 4096 was not great at least on Safari 15.
		bufferSizeInBytes = 8192 * channelCount
	}

	buf32 := make([]float32, bufferSizeInBytes/4)

	if w := d.audioContext.Get("audioWorklet"); w.Truthy() {
		script := fmt.Sprintf(`
class OtoWorkletProcessor extends AudioWorkletProcessor {
	constructor() {
		super();
		this.bufferSize_ = %[1]d;
		this.channelCount_ = %[2]d;
		this.buf_ = new Float32Array();
		this.waitRecv_ = false;

		// Receive data from the main thread.
		this.port.onmessage = (event) => {
			const buf = event.data;
			const newBuf = new Float32Array(this.buf_.length + buf.length);
			newBuf.set(this.buf_);
			newBuf.set(buf, this.buf_.length);
			this.buf_ = newBuf;
			this.waitRecv_ = false;
		}
	}

	process(inputs, outputs, parameters) {
		const output = outputs[0];

		// If the buffer is too short, request more data and return silence.
		if (this.buf_.length < output[0].length*this.channelCount_) {
			if (!this.waitRecv_) {
				this.waitRecv_ = true;
				this.port.postMessage(null);
			}
			for (let i = 0; i < output.length; i++) {
				output[i].fill(0);
			}